Japanese statesman, born in 1841, being the son of Ito Juzo, and (like his father) began life as a retainer of the lord of Choshu, one of the most powerful nobles of Japan. Choshu, in common with many of his fellow Daimyos, was bitterly opposed to the rule of the shogun, and when this rule resulted in the conclusion of the treaty with Commodore Matthew Perry in 1854, the smouldering discontent broke out into open hostility against both parties to the compact. In these views Ito cordially agreed with his chieftain, and was sent on a secret mission to Yedo to report to his lord on the doings of the government. This visit had the effect of causing Ito to turn his attention seriously to the study of the British and of other military systems. As a result he persuaded Choshu to remodel his army, and to exchange the bows and arrows of his men for guns and rifles. But Ito felt that his knowledge of foreigners, if it was to be thorough, should be sought for in Europe, and with the connivance of Choshu he, in company with Inouye and three other young men of the same rank as himself, determined to risk their lives by committing the then capital offense of visiting a foreign country. With great secrecy they made their way to Nagasaki, where they concluded an arrangement with the agent of Messrs. Jardine, Matheson & Co. for passages onboard a vessel which was about to sail for Shanghai (1863). At that port the adventurers separated, three of their number taking ship as passengers to London, while Ito and Inouye preferred to work their passages before the mast in the "Pegasus", bound for the same destination. For a year these two friends remained in London studying English methods, but then events occurred in Japan which recalled them to their country. The treaties lately concluded by the shogun with the foreign powers conceded the right to navigate the strait of Shimonoseki, leading to the Inland Sea. On the northern shores of this strait stretched the feudal state ruled over by Prince Choshu, who refused to recognize the clause opening the strait, and erected batteries on the shore, from which he opened fire on all ships which attempted to force the passage. The shogun having declared himself unable in the circumstances to give effect to the provision, the treaty powers determined to take the matter into their own hands. Ito, who was better aware than his chief of the disproportion between the fighting powers of Europe and Japan, memorialized the cabinets, begging that hostilities should be suspended until he should have had time to use his influence with Choshu in the interests of peace. With this object Ito hurried back to Japan. But his efforts were futile. Choshu refused to give way, and suffered the consequences of his obstinacy in the destruction of his batteries and in the infliction of a heavy fine. The part played by Ito in these negotiations aroused the animosity of the more reactionary of his fellow clansmen, who made repeated attempts to assassinate him. On one notable occasion he was pursued by his enemies into a tea-house, where he was concealed by a young lady beneath the floor of her room. Thus began a romantic acquaintance, which ended in the lady becoming the wife of the fugitive. Subsequently (1868) Ito was made governor of Hiogo, and in the course of the following year became vice-minister of finance. In 1871 he accompanied Iwakura on an important mission to Europe, which, though diplomatically a failure, resulted in the enlistment of the services of European authorities on military, naval and educational systems.

After his return to Japan Ito served in several cabinets as head of the bureau of engineering and mines, and in 1886 he accepted office as prime minister, a post which, when he resigned in 1901, he had held four times. In 1882 he was sent on a mission to Europe to study the various forms of constitutional government; on this occasion he attended the coronation of the Tsar Alexander III. On his return to Japan he was entrusted with the arduous duty of drafting a constitution. In 1890 he reaped the fruits of his labors, and nine years later he was destined to witness the abrogation of the old treaties, and the substitution in their place of conventions which place Japan on terms of equality with the European states. In all the great reforms in the Land of the Rising Sun Ito played a leading part. It was mainly due to his active interest in military and naval affairs that he was able to meet Li Hung-chang at the end of the Chinese and Japanese War (1895) as the representative of the conquering state, and the conclusion of the Anglo-Japanese Alliance in 1902 testified to his triumphant success in raising Japan to the first rank among civilized powers. As a reward for his conspicuous services in connection with the Chinese War Ito was made a marquis, and in 1897 he accompanied Prince Arisugawa as a joint representative of the Mikado at the Diamond Jubilee of Queen Victoria. At the close of 1901 he again, though in an unofficial capacity, visited Europe and the United States; and in England he was created a G.C.B. After the Russo-Japanese War (1905) he was appointed resident general in Korea, and in that capacity he was responsible for the steps taken to increase Japanese influence in that country. In September 1907 he was advanced to the rank of prince. He retired from his post in Korea in July 1909, and became president of the privy council in Japan. But on the 26th of October, when on a visit to Harbin, he was shot dead by a Korean assassin.